Improvement in key-fasteners



UNITED STATES PATENT OFFICE.

IMPROVEMENT IN KEY-FASTENERS.

Specification forming part of Letters Patent No. 56,933,4 dated August 7, 1866.

To all whom it may concern:

Beit known that I, MARSHALL P. HALL, of Manchester, in the county of Hillsborough and State ot' New Hampshire, have invented a new and Improved Method of Preventing the Turning of Keys and Moving of Bolts in Locks; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

This invention is intended to be applied to the locks of dwellings, chambers, hotel-rooms, and all apartments Whose inmates desire effectual protection against the picking of locks by persons outside.

It consists of a piece of metal, a, (shown in lFigure 1,) having one end tapered so as to enter key-holes of different sizes,.and provided with notches b on the under side, and with a slot, s, in which movesa clamp, o, having a nut, n, on the under side. Between the nut n and the piece a is a Washer, w, provided with aY tooth, t, Fig. 3, made to t the notches in the piece a.. This prevents the piece cfroui being driven by force out of' the lock.

Its application is as follows: The door is locked and the key left with the ring in a horizontal position. The tapered end of the in-- strument is then inserted in the key-hole below the key, the clamp passing up inside the ring.

The clamp is then turned so as to bear on the top of the key, and the nut turned up tightly,

takin g care to force the instrument well in, to

pull the key and clamp out, so as to leave no room for play, and to fit the tooth t, on the washer'w, into the proper notch.

It will be seen that a key having this instrument properly applied cannot be turned from the outside by any means; neither can the lock be picked by wires or false keys, because the bolt is protected by the key and by the instrument. Thus an ordinary and cheap lock is rendered as efficient as one costly and coinplicated.

What I claim as new and novel, and desire to secure by Letters Patent, is-

The device herein described--that is to say, the notched piece a, or its equivalent, entering the key-hole at one point, and secured to the key at another point by the clamp 0 the washer w, and the nut a, or their equivalents.

` MARSHALL Pi. HALL. Witnesses:

NATHL. E. MORRTLL, JOSEPH HALL. 

